If you recently unlocked your iPhone 4 and tried to run it on a T-Mobile US SIM, you must have noticed that MMS doesn’t work anymore. Well good news is that there is now a fix available in Cydia which will fix this problem once and for all.
NOTE: You will need to have a jailbroken iPhone to get it to work. Follow the step by step guideposted here to jailbreak your iPhone 4, 3GS and 3G on iOS 4.0.1. Instructions for unlocking iPhone 4 can be found here, and for iPhone 3GS and 3G can be found here.
Step 1: Start “Cydia” on your iPhone. Touch on “Manage” tab on the bottom, and then on“Sources” as seen in the screenshot below:
Step 2: Now touch on “Edit” and then on “Add”. You will be prompted to enter a url source as seen in the screenshot below. Type “http://cydia.pushfix.info” and touch on“Add Source” to add this repo if you haven’t already.
Cydia will now automatically update your sources by following a series of automated steps.
MMS Proxy: 126.96.36.199:8080
MMS Max Message Size: 1048576
MMS UA Prof URL: http://www.apple.com/mms/uaprof.rdf